EP1383231B1 - Method for acquiring the magnetic flux, the rotor position and/or the rotation speed - Google Patents

Description

The invention relates to a method for detecting the magnetic flux of the rotor, the rotor position and / or the rotational speed of the rotor in a single or multi-phase permanent magnet or synchronous motor or generator according to the features indicated in the preamble of claim 1.

$$L\cdot {\dot{i}}_{\beta }=-R\cdot i_{\beta }-p\cdot \omega \cdot {\psi }_{\mathit{m\alpha }}+u_{\beta }$$

in denen
L  die Induktivität
i_α  der Strom in Richtung α
i_β  der Strom in Richtung β

  die zeitliche Ableitung des Stroms in Richtung α

  die zeitliche Ableitung des Stroms in Richtung β
R  der ohmsche Widerstand
p  die Polpaarzahl
ω  die Drehzahl des Rotors
ψ_mα  der magnetische Fluss in Richtung α im Rotor
ψ_mβ  der magnetische Fluss in Richtung β im Rotor
u_α  die Spannung in Richtung α
u_β  die Spannung in Richtung β sind, definiert. Wie sich aus diesen Gleichungen ergibt, können die vorgenannten Größen ermittelt werden, wenn Spannung und Strom in den Richtungen ∀ und ∃ bekannt sind. Letztere können als elektrische Daten in einfacher Weise erfasst werden. Allerdings ist dies nach dem Stand der Technik nur möglich, wenn der Betrag des magnetischen Flusses als konstant angenommen wird, da sonst das Gleichungssystem aufgrund zu vieler Unbekannter nicht eindeutig lösbar ist. Da der magnetische Fluss tatsächlich aber nicht konstant ist, sondern der Betrag über Zeit und Rotorposition variiert, ist dieses bekannte Verfahren fehlerbehaftet, was dazu führt, dass es für den Einsatz im Steuerungs- und Regelungsprozessen des Motors nur bedingt geeignet ist.Magnetic flux, rotor position and speed are determined by the stator voltage equations known per se: $$L\cdot {\dot{i}}_{\alpha }=-R\cdot i_{\alpha }+p\cdot \omega \cdot {\psi }_{\mathit{m\beta }}+u_{\alpha }$$

$$L\cdot {\dot{i}}_{\beta }=-R\cdot i_{\beta }-p\cdot \omega \cdot {\psi }_{\mathit{m\alpha }}+u_{\beta }$$

in which
L is the inductance
i _{α is} the current in the direction α
i _{β is} the current in the direction β

the time derivative of the current in the direction of α

the time derivative of the current in the direction of β
R the ohmic resistance
p the pole pair number
ω the speed of the rotor
ψ _{mα is} the magnetic flux in the direction α in the rotor
ψ _mβ the magnetic flux towards β in the rotor
u _{α is} the tension in the direction α
u _{β are} the stress in the direction β, Are defined. As can be seen from these equations, the above quantities can be determined when voltage and current in directions ∀ and ∃ are known. The latter can be easily detected as electrical data. However, this is only possible in the prior art if the magnitude of the magnetic flux is assumed to be constant, since otherwise the system of equations can not be solved unambiguously because of too many unknowns. Since the magnetic flux is actually not constant, but the amount varies over time and rotor position, this known method is subject to errors, which means that it is only of limited suitability for use in the control and regulation processes of the engine.

Modern multi-phase permanent magnet motors are nowadays often provided with power electronics, i. H. the commutation is done electronically. To control this commutation, however, knowledge of the current rotor position is of crucial importance, not only to operate the motor with high efficiency, but also to protect the sensitive components of the power electronics and to achieve a better dynamic behavior of the drive.

Out US 2001/0017529 A1 It belongs to the state of the art to start a synchronous motor by means of a pulse width modulation by means of a vector control of the motor. However, the stator flux and not the rotor flux is taken into account.

Out WO 99/65137 A1 It is state of the art to determine the stator flux on the basis of a current model of the synchronous motor for determining the rotor position of a synchronous motor.

Out US 5,729,102 A1 is a vector control known, with which the rotor position is detected. A detection of the magnetic flux in the rotor is not provided there.

Although the speed measurement can still be comparatively easy via an external measuring arrangement. The exact determination of the rotor position, however, is expensive.

On the other hand, it is endeavored to determine these values as far as possible mathematically, because due to the regular control and part of the engine electronics digital electronics, appropriate computing power is available or at least with little effort available adjustable. Corresponding programs for computational Investigations could therefore be integrated without much effort through software implementation.

Against this background, the invention has for its object to improve a generic method for detecting the magnetic flux, the rotor position and / or the rotational speed of the rotor in a single or Mehrphasenpermanentmagnet- or synchronous motor or generator.

This object is achieved by the features specified in claim 1. Advantageous embodiments of the invention are specified in the subclaims and the following description.

The basic idea of the present invention is to use the stator voltage equations known per se in the method for detecting the aforementioned quantities, but, unlike the prior art, not to set the magnetic flux constant but to incorporate the energy relationships in the magnet of the rotor so that the aforementioned variables, in particular the rotor position or its time derivative, to be able to determine the speed more accurate.

The present invention is applicable to both single-phase and multi-phase permanent magnet or synchronous motors as well as corresponding generators. As far as single-phase motors or generators are concerned, one of the two stator voltage equations is eliminated. Incidentally, in two or more-phase motors or generators in principle with the stator voltage equation for two-phase motors and generators is calculated, is reduced in three-phase and multi-phase motors arithmetically in a conventional manner to a two-phase model or transformed so far must then metrologically recorded values be converted accordingly to a two-phase model.

The present method is particularly intended for permanent magnet motors, but can also be applied in the same way in synchronous motors or generators, wherein in synchronous motors or generators of the magnet formed by the rotor coil occurs in place of the permanent magnet. A generator application in this sense can also be given in connection with the control of motors powered by power electronics, if they feed into the grid during generator operation in order to determine the rotor position of the network generator.

The inventive method can also be used for generators, for example in the control

In Fig. 1 is such an equivalent circuit diagram of a two-phase permanent magnet motor is shown, there are two offset by 90 ° to each other arranged phases α and β provided in a stator 1, which are symbolized by two coils 3 and 4. Within this stator 1, a rotor 2 is arranged, which has a permanent magnet 5 with diametral polarity distribution N and S, which is rotatably mounted within the stator 1.

$${\dot{\psi }}_{\mathit{m\beta }}=p\cdot \omega \cdot {\psi }_{\mathit{m\alpha }}$$

wobei

ψ̇_mα

die zeitliche Ableitung von ψ_mα und

ψ̇_mβ

die zeitliche Ableitung von ψ_mβ sind.

In order to consider the energy ratios in the magnet 5 of the rotor 2, the following equations (3) and (4) are used. $${\dot{\psi }}_{\mathit{m\alpha }}=-p\cdot \omega \cdot {\psi }_{\mathit{m\beta }}$$

$${\dot{\psi }}_{\mathit{m\beta }}=p\cdot \omega \cdot {\psi }_{\mathit{m\alpha }}$$

in which

ψ̇ _mα

the time derivative of ψ _mα and

ψ̇ _mβ

are the time derivative of ψ _mβ .

The peculiarity of these rotor energy equations lies in the fact that the magnetic flux in the ß - direction flows into the time derivative of the magnetic flux in the α - direction and vice versa.

This results in a mathematical engine model with which, for example, as based on Fig. 2 illustrated, electrical, magnetic and / or mechanical values of the engine can be determined.

In the following motor models shown block-wise in the figures, a calculated value is indicated by,, whereas in the case of the values marked without ^ these are measured values.

It is understood that one of the variables mentioned in the introduction (magnetic flux, rotor position, rotational speed) can be determined in each case if this is indicated by the block 6 in FIG Fig. 2 symbolized engine model is used. This motor model symbolized by the block 6 consists of the equations (1) to (4), with which one of the abovementioned values can be computationally determined comparatively accurately.

$$L\cdot {\dot{\hat{i}}}_{\beta }=-R\cdot {\hat{i}}_{\beta }-p\cdot \hat{\omega }\cdot {\hat{\psi }}_{\mathit{m\alpha }}+u_{\beta }$$

$${\dot{\hat{\psi }}}_{\mathit{m\alpha }}=-p\cdot \hat{\omega }\cdot {\hat{\psi }}_{\mathit{m\beta }}$$

$${\dot{\hat{\psi }}}_{\mathit{m\beta }}=-p\cdot \hat{\omega }\cdot {\hat{\psi }}_{\mathit{m\alpha }}$$

In the method according to Fig. 2 the voltages u _α and u _β , ie the stator voltages in the α and β directions are measured or otherwise calculated or made available, likewise ω the rotor speed. These quantities are used in equations (1) to (4), so that mathematically the speed of the magnetic flux ω _flux , the motor currents i _α in the direction α and i _β in the direction β and the magnetic flux ψ _α in the direction α and ψ _β in the direction β can be determined. The calculated values are marked with ^: $$L\cdot {\dot{\hat{i}}}_{\alpha }=-R\cdot {\hat{i}}_{\alpha }+p\cdot \hat{\omega }\cdot {\hat{\psi }}_{\mathit{m\beta }}+u_{\alpha }$$

$$L\cdot {\dot{\hat{i}}}_{\beta }=-R\cdot {\hat{i}}_{\beta }-p\cdot \hat{\omega }\cdot {\hat{\psi }}_{\mathit{m\alpha }}+u_{\beta }$$

$${\dot{\hat{\psi }}}_{\mathit{m\alpha }}=-p\cdot \hat{\omega }\cdot {\hat{\psi }}_{\mathit{m\beta }}$$

$${\dot{\hat{\psi }}}_{\mathit{m\beta }}=-p\cdot \hat{\omega }\cdot {\hat{\psi }}_{\mathit{m\alpha }}$$

verwendet, die Position ρ des magnetischen Flusses ermittelt werden. In diesem grundlegenden Motormodell 6 wird die Rotorposition durch Gleichsetzung mit der Position des magnetischen Flusses bestimmt, davon ausgehend, dass diese real stets übereinstimmen.From the magnetic flux ψ _α in the direction α and ψ _β in the direction β can then by means of an angle calculator 7, the geometric designation according to $$\rho =\frac{1}{p}\cdot \mathit{arctan}\left(\frac{{\psi }_{\mathit{m\beta }}}{{\psi }_{\mathit{m\alpha }}}\right)$$

used, the position ρ of the magnetic flux can be determined. In this basic motor model 6, the rotor position is determined by equating with the position of the magnetic flux, assuming that they always coincide in real terms.

$$L\cdot {\dot{i}}_{\beta }=-R\cdot i_{\beta }-p\cdot \omega \cdot {\psi }_{\mathit{m\alpha }}+u_{\beta }+{\upsilon }_{1\beta }$$

$${\dot{\psi }}_{\mathit{m\alpha }}=-p\cdot \omega \cdot {\psi }_{\mathit{m\beta }}+{\upsilon }_{2\alpha }$$

$${\dot{\psi }}_{\mathit{m\beta }}=p\cdot \omega \cdot {\psi }_{\mathit{m\alpha }}+{\upsilon }_{2\beta }$$

in denen

υ _1a,υ _{1 β},υ _2α,υ _2β

Korrekturglieder sind.

Since this engine model 6 in its simplest form represents only a mathematical approximation to the actual values, it can be improved by further measures. Such an improvement is for example the basis of Fig. 3 represented method. How the Fig. 3 The basic motor model 6, consisting of equations (1) to (4), is also used as the basis, the stator voltages u in the direction α and β, u _α and u _β, and the rotor speed ω, for example, as measured variables in the model incorporated. Unlike the method after Fig. 2 However, in the model 6a after Fig. 3 the stator current in α- and β-direction, ie i _α and i _β additionally detected, is linked to the calculated current values î _α and î _β determined by the motor model 6a by subtraction (this is in Fig. 3 represented by the subtraktorische link 8) and the resulting value supplied to a correction member 9, which flows into the motor model 6a corrective. In this way, a refined motor model 6a and thus an improved method for determining the aforementioned values is provided, which consists of the equations (1a), (2a), (3a) and (4a): $$L\cdot {\dot{i}}_{\alpha }=-R\cdot i_{\alpha }+p\cdot \omega \cdot {\psi }_{\mathit{m\beta }}+u_{\mathit{\alpha }}+{\mathrm{<figure-callout\; id="1"\; label="\upsilon "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\upsilon </figure-callout>}}_{\mathit{1}\mathit{\alpha }}$$

$$L\cdot {\dot{i}}_{\beta }=-R\cdot i_{\beta }-p\cdot \omega \cdot {\psi }_{\mathit{m\alpha }}+u_{\beta }+{\mathrm{<figure-callout\; id="1"\; label="\upsilon "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\upsilon </figure-callout>}}_{1\beta }$$

$${\dot{\psi }}_{\mathit{m\alpha }}=-p\cdot \omega \cdot {\psi }_{\mathit{m\beta }}+{\mathrm{<figure-callout\; id="2"\; label="\upsilon "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\upsilon </figure-callout>}}_{2\alpha }$$

$${\dot{\psi }}_{\mathit{m\beta }}=p\cdot \omega \cdot {\psi }_{\mathit{m\alpha }}+{\mathrm{<figure-callout\; id="2"\; label="\upsilon "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\upsilon </figure-callout>}}_{2\beta }$$

in which

υ _1a , υ _{1 β} , υ _2α , υ _{2 β}

Correction members are.

In the method according to Fig. 3 the measured stator currents in the α and β directions are provided as a correction element in comparison to the calculated currents in the α and β directions. It is understood that this is to be understood only as an example, the motor currents can be incorporated into the motor model 6 or 6a in the same way, and the motor voltages can be calculated and optionally incorporated as a correction element by comparison with the actual voltages. It can also be provided a plurality of correction members which are constructed on the basis of a plurality of electrical variables.

$$L\cdot {\hat{i}}_{\beta }=-R\cdot i_{\beta }-p\cdot \hat{\omega }\cdot {\hat{\psi }}_{\mathit{m\alpha }}+u_{\beta }+{\upsilon }_{1\beta }$$

$${\dot{\hat{\psi }}}_{\mathit{m\alpha }}=-p\cdot \hat{\omega }\cdot {\hat{\psi }}_{\mathit{m\beta }}+{\upsilon }_{2\alpha }$$

$${\hat{\psi }}_{\mathit{m\beta }}=p\cdot \hat{\omega }\cdot {\hat{\psi }}_{\mathit{m\alpha }}+{\upsilon }_{2\beta }$$

in denen

υ_1α,υ _{1 β},υ _2α ,υ _2β

Korrekturglieder sind,

wobei die Korrekturglieder durch einen Korrekturfaktor und die Differenz der errechneten elektrischen Werte und der gemessenen elektrischen Werte wie folgt gebildet sind: $${\upsilon }_{1\alpha }=K_i\cdot \left({\hat{i}}_{\alpha }-i_{\alpha }\right)$$

$${\upsilon }_{2\alpha }=-K_{\psi }\cdot \left({\hat{i}}_{\beta }-i_{\beta }\right)$$

$${\upsilon }_{1\beta }=K_i\cdot \left({\hat{i}}_{\beta }-i_{\beta }\right)$$

$${\upsilon }_{2\beta }=K_{\psi }\cdot \left({\hat{i}}_{\alpha }-i_{\alpha }\right)$$

For that, based on Fig. 3 By way of example and method described by way of example, the following equations result by way of example $$L\cdot {\hat{i}}_{\alpha }=-R\cdot i_{\alpha }+p\cdot \hat{\omega }\cdot {\hat{\psi }}_{\mathit{m\beta }}+u_{\alpha }+{\mathrm{<figure-callout\; id="1"\; label="\upsilon "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\upsilon </figure-callout>}}_{\mathit{1}\alpha }$$

$$L\cdot {\hat{i}}_{\beta }=-R\cdot i_{\beta }-p\cdot \hat{\omega }\cdot {\hat{\psi }}_{\mathit{m\alpha }}+u_{\beta }+{\mathrm{<figure-callout\; id="1"\; label="\upsilon "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\upsilon </figure-callout>}}_{1\beta }$$

$${\dot{\hat{\psi }}}_{\mathit{m\alpha }}=-p\cdot \hat{\omega }\cdot {\hat{\psi }}_{\mathit{m\beta }}+{\mathrm{<figure-callout\; id="2"\; label="\upsilon "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\upsilon </figure-callout>}}_{2\alpha }$$

$${\hat{\psi }}_{\mathit{m\beta }}=p\cdot \hat{\omega }\cdot {\hat{\psi }}_{\mathit{m\alpha }}+{\mathrm{<figure-callout\; id="2"\; label="\upsilon "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\upsilon </figure-callout>}}_{2\beta }$$

in which

υ _1α , υ _{1 β} , υ _2α , υ _{2 β}

Correction members are,

wherein the correction terms are formed by a correction factor and the difference of the calculated electrical values and the measured electrical values as follows: $${\upsilon }_{1\alpha }=K_i\cdot \left({\hat{i}}_{\alpha }-i_{\alpha }\right)$$

$${\upsilon }_{2\alpha }=-K_{\psi }\cdot \left({\hat{i}}_{\beta }-i_{\beta }\right)$$

$${\upsilon }_{1\beta }=K_i\cdot \left({\hat{i}}_{\beta }-i_{\beta }\right)$$

$${\upsilon }_{2\beta }=K_{\psi }\cdot \left({\hat{i}}_{\alpha }-i_{\alpha }\right)$$

As apparent from the above equations, the correction terms ν ₂ are formed to be formed in the equations (3a) and (4a) in the one phase by means of the difference between calculated and measured currents of the other phase. The variables K _i and K _ψ each form a constant factor.

In Fig. 4 exemplified a development of the method according to the invention, in which in addition to the corrected engine model 6a according to Fig. 3 a further development is provided to the effect that the rotor speed ω is determined by calculation. In the engine models according to the FIGS. 2 and 3 the rotor speed ω enters as an input quantity. Then, the speed is usually detected by sensors, preferably by means of a Hall sensor, as is also known per se.

However, there are constellations in which the rotor speed must also be determined by calculation or in which the sensory measured values are not sufficiently accurate or are available in time in only relatively large distances. For these cases is in one According to a further development of the invention, an adaptation block 10 is provided, which approximates the determined speed to the actual rotor speed by means of a speed correction element 11, in which the difference between an assumed or calculated speed and the flow velocity ω _flux calculated by the motor model 6a is approximated, until the speed correction element 11 approaches the value Zero assumes. This correction element 11 is in Fig. 4 as a result of the sub-tractive linkage made in node 14 and assumes that the velocity of the magnetic flux and the rotor velocity must always coincide. In the adaptation block 10, therefore, the difference determined by means of the speed correction element 11 is always added to the previously determined speed taking into account a correction factor and output as a new calculated speed. This new calculated speed then flows, on the one hand, into the engine model 6a and, on the other hand, arrives at the node 14, which also receives a new speed of magnetic flux due to the new speed which has flowed into the engine model 6a and thereby outputs a new speed correction element 11, which outputs the above-described approach process introduced again by the adaptation block 10, until finally the correction element 11 assumes the value zero, that is, the speed of the magnetic flux, as determined from the motor model 6a, and the rotor speed, so the calculated speed of the rotor match.

wobei $\frac{1}{p}\cdot \frac{{\upsilon }_{2\beta }\cdot {\hat{\psi }}_{\mathit{m\alpha }}-{\upsilon }_{2\alpha }\cdot {\hat{\psi }}_{\mathit{m\beta }}}{{{\hat{\psi }}^2}_{\mathit{m\alpha }}+{{\hat{\psi }}^2}_{\mathit{m\beta }}}$

das Drehzahlkorrekturglied 11 darstellt. Within the motor model 6a, the speed of the magnetic flux is formed by time derivative of the detected position of the magnetic flux. Thus, if we derive equation (5) in time to obtain the velocity of the magnetic flux and insert equations (3a) and (4a) into equation (5) derived therefrom, the velocity of the magnetic flux is as follows : $$\dot{\hat{\rho }}={\omega }_{\mathit{Flux}}=\hat{\omega }+\frac{1}{p}\cdot \frac{{\mathrm{<figure-callout\; id="2"\; label="\upsilon "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\upsilon </figure-callout>}}_{2\beta }\cdot {\hat{\psi }}_{\mathit{m\alpha }}-{\mathrm{<figure-callout\; id="2"\; label="\upsilon "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\upsilon </figure-callout>}}_{2\alpha }\cdot {\hat{\psi }}_{\mathit{m\beta }}}{{{\hat{\psi }}^2}_{\mathit{m\alpha }}+{{\hat{\psi }}^2}_{\mathit{m\beta }}}$$

in which $\frac{1}{p}\cdot \frac{{\mathrm{<figure-callout\; id="2"\; label="\upsilon "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\upsilon </figure-callout>}}_{2\beta }\cdot {\hat{\psi }}_{\mathit{m\alpha }}-{\mathrm{<figure-callout\; id="2"\; label="\upsilon "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\upsilon </figure-callout>}}_{2\alpha }\cdot {\hat{\psi }}_{\mathit{m\beta }}}{{{\hat{\psi }}^2}_{\mathit{m\alpha }}+{{\hat{\psi }}^2}_{\mathit{m\beta }}}$

the speed correction member 11 represents.

The adaptation block 10 forms part of an approximation process in which the assumed or calculated speed is brought into agreement with the actual rotor speed with the aid of the motor model 6a, the speed correction element 11, until the speed correction element becomes zero.

wobei
Δω_mess das zusätzliche Drehzahlkorrekturglied 15 bildet und K_v eine Konstante. In addition, the difference between the calculated in the adaptation block 10 rotor speed and a measured rotor speed can be taken into account, such an additional speed correction element 15 is additively linked in the node 12 with the speed correction element 11, which is formally represented as follows: $$\mathrm{\Delta }{\omega }_{\mathit{mess}}=K_V\cdot \left(\stackrel{⁀}{\omega }-{\omega }_{\mathit{rotor}}\right)$$

in which
Δω _{measurement forms} the additional speed _{correction element} 15 and K _{v is} a constant.

If no measured rotor speed is available this additional speed correction element 15 is equal to zero. Kv represents a gain factor with which this additional speed correction element 15 flows.

Additionally, according to FIG. 5 the speed may also be determined by means of a system speed change correction element 13, which may be derived from a speed model. The procedure differs from that based on FIG. 4 described above in that in addition to the adaptation block 10, a system speed change correction element 13 derived from the speed model occurs.

in der

M

das antreibende Moment

M_L

das Lastmonent

J

das Massenträgheitsmoment der rotierenden Last sind.

The speed model contains more information about the mechanical relationships of the drive system. Expediently, the change in the rotational speed, that is to say the temporal change of the rotor speed, is expressed by a mechanical equation of state which takes into account the aforementioned mechanical relationships. The change in the rotational speed can be taken into account by the following equation in the rotational speed model 13: $$\dot{\omega }=\frac{1}{J}\cdot \left(M-M_L\right)$$

in the

M

the driving moment

M _L

the load month

J

are the moment of inertia of the rotating load.

This state equation, which is known per se, states that a speed change occurs only when the drive torque is greater than the load torque or vice versa, and that this change is then dependent on the difference moment as well as the mass moment of inertia of the rotating load.

This additional information leads in conjunction with the adaptation block 10 with changing speed faster to the result in which the calculated speed of the rotor corresponds to the actual speed and is thus particularly suitable for highly dynamic drive tasks. However, the speed model assumes that appropriate mechanical or electrical quantities are available, for example, by measurement or otherwise. If necessary, the speed model can also be simplified by making clever statements.

For example, if the engine is running at a constant speed and the speed model is being used to determine the speed, then equation (8) will yield zero so that the speed model will not actually be used, but rather the speed as based on FIG. 4 is determined described. The assumption that the engine is running at a constant speed, therefore, is not about the basis of FIG. 4 described out.

wobei

Δω_System

- das Systemänderungskorrekturglied und

K₄

- die Konstante sind.

By contrast, equation (8) can be simplified by specific load assumptions, for example by the load state M _L = 0 or const. The load torque is often unknown or can only be determined with difficulty. In many cases, however, a constant load moment can be assumed. In this assumption, the system speed change correction member 13 then has the form: $$\mathrm{\Delta }{\omega }_{\mathit{system}}=\frac{1}{J}\cdot \left(M-{\mathrm{<figure-callout\; id="4"\; label="M"\; filenames="imgf0002.png"\; state="\{\{state\}\}">M</figure-callout>}}_4\right)$$

in which

Δ ω _system

the system change correction term and

K ₄

- are the constant.

The constant K ₄ is zero when the load torque is assumed to be zero. Incidentally, the constant K ₄ for the respective type and type of unit to be determined in advance.

in der

K ₂

eine Konstante ist,

The drive torque is determined by equation (10): $$M={\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">K</figure-callout>}}_2\cdot \left({\psi }_{\mathit{m\alpha }}\cdot i_{\beta }-{\psi }_{\mathit{m\beta }}\cdot i_{\alpha }\right).$$

in the

K ₂

a constant,

The parenthesized Therm in equation (10) is already known from the motor model 6a. Substituting equation (10) into equation (9), it will be seen that for this case (assuming that the load moment is zero or constant) the system change correction term 13 can calculate from the engine model 6a out. It is therefore possible to determine this correction element 13 without further measurement and thus calculate the speed of the rotor faster or more accurately. It is thus particularly favorable if the drive torque can be determined from the variables derived from the engine model 6a.

in der

K ₁

eine Konstante ist,

die eine Beziehung zur Rotordrehzahl schafft. Auch hier können aus dem Motormodell 6a abgeleitete Größen in das Drehzahlmodell einfließen ohne dass weitere mechanische oder elektrische Messungen erforderlich sind.If the motor is used, for example, in a centrifugal pump unit, then the load torque can be determined in a simple manner by calculation, since it is determined by the equation (11): $$M_L={\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">K</figure-callout>}}_{\mathit{1}}\cdot {\mathrm{<figure-callout\; id="2"\; label="\omega "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\omega </figure-callout>}}^2.$$

in the

K ₁

a constant,

which creates a relationship to the rotor speed. Here, too, variables derived from the engine model 6a can be included in the speed model without the need for further mechanical or electrical measurements.

Irrespective of whether the rotational speed is determined only by means of the adaptation model 10 or additionally taking into account a rotational speed model, a measured rotational speed can also be included in order to achieve the desired result more quickly or to increase the accuracy of the calculated values. Such a fast and accurate detection of engine operating variables, as can be done by the above-described method according to the invention, is the prerequisite for a dynamic and stable motor drive.

The above-described methods can be implemented by software in a digital engine electronics without further ado. The constant detection and storage of the corresponding electrical values of the motor, so the motor currents and voltages is one of the applied state of the art today, so these data are on the control side Anyway available, so that the present invention may be applied without any structural change within the digital engine control to improve them.

LIST OF REFERENCE NUMBERS

1

- stator

2

- Rotor

3

- Kitchen sink

4

- Kitchen sink

5

- permanent magnet

6

Motor model 6a in FIG.

7

- Angle calculator

8th

- Shortcut

9

- correction element

α

- Direction

β

- Direction

N

- North pole of the magnet

S

- South pole of the magnet

10

- Adaptation block

11

- Speed correction element

12

- node

13

- System speed change correction element

14

- node

15

- additional speed correction element

Claims (19)

1. A method for detecting the magnetic flux of the rotor, the rotor position and/or the speed of the rotor, in a single-phase or multiphase permanent magnet motor or in a single-phase or multiphase synchronous motor or in a single-phase or multiphase generator, whilst applying the stator voltage equations $$L\cdot {\dot{i}}_{\alpha }=-R\cdot i_{\alpha }+p\cdot \omega \cdot {\psi }_{\mathit{m\beta }}+u_{\alpha }$$

   

   $$L\cdot {\dot{i}}_{\beta }=-R\cdot i_{\beta }-p\cdot \omega \cdot {\psi }_{\mathit{m\alpha }}+u_{\beta }$$

   

   in which

   L is the inductance

   i_α the current in the direction α

   i_β the current in the direction β

   

   the temporal derivative of the current in the direction α

   

   the temporal derivative of the current in the direction β

   R the ohmic resistance

   p the pole pair number

   ω the speed of the rotor

   ψ_mα the magnetic flux in the direction α

   ψ_mβ the magnetic flux in the direction β

   u_α the voltage in the direction α

   u_β the voltage in the direction β

   characterised in that with regard to the evaluations, the energy conditions in the magnet (5) of the rotor (2) are taken into account by way of the following energy equations: $${\dot{\psi }}_{\mathit{m\alpha }}=-p\cdot \omega \cdot {\psi }_{\mathit{m\beta }}$$

   

   $${\dot{\psi }}_{\mathit{m\beta }}=p\cdot \omega \cdot {\psi }_{\mathit{m\alpha }}$$

   

   wherein

   ψ̇_mα is the temporal derivative of ψ_mα and

   ψ̇_mβ the temporal derivative of ψ_mβ.
2. Method according to claim 1, characterised in that the motor model which is defined by the equations (1) to (4) is corrected in dependence on a comparison between computed model values (^) and measured electrical and/or mechanical values, by way of at least one correction term (9), so that the following equations result: $$L\cdot {\dot{i}}_{\alpha }=-R\cdot i_{\alpha }+p\cdot \omega \cdot {\psi }_{\mathit{m\beta }}+u_{\mathit{\alpha }}+{\upsilon }_{\mathit{1}\mathit{\alpha }}$$

   

   $$L\cdot {\dot{i}}_{\beta }=-R\cdot i_{\beta }-p\cdot \omega \cdot {\psi }_{\mathit{m\alpha }}+u_{\beta }+{\upsilon }_{1\beta }$$

   

   $${\dot{\psi }}_{\mathit{m\alpha }}=-p\cdot \omega \cdot {\psi }_{\mathit{m\beta }}+{\upsilon }_{2\alpha }$$

   

   $${\dot{\psi }}_{\mathit{m\beta }}=p\cdot \omega \cdot {\psi }_{\mathit{m\alpha }}+{\upsilon }_{1\beta }$$

   

   in which

   υ_1α,υ _{1 β},υ _{2 α},υ _1β are correction terms.
3. A method according to claim 2, characterised in that the measured electrical values are the motor currents.
4. A method according to one of the preceding claims, characterised in that the correction terms (9) are formed in each case from one correction factor and the difference between measured and computed motor currents.
5. A method according to one of the preceding claims, characterised in that the correction terms (9) in the Equations (3a) and (4a) in the one phase are formed by way of the difference between the measured and the computed currents of the other phase, wherein the correction term enters the equation (3a) with a negative sign.
6. A method according to one of the preceding claims, characterised in that the speed is detected sensorically.
7. A method according to claim 6, characterised in that the speed is determined with the help of a Hall sensor
8. A method according to one of the preceding claims, characterised in that the speed is determined by computation, in a manner such that the difference between the flux speed and an assumed rotor speed or variables derived therefrom is formed as a speed correction term (11), and the current speed is determined by an approximation process from this.
9. A method according to claim 8, characterised in that the speed correction term (11) is corrected by way of a speed measurement.
10. A method according to one of the preceding claims, characterised in that the assumed rotor speed is adapted to the current speed in an adapter block (10) by way of the speed correction term (11).
11. A method according to one of the preceding claims, characterised in that the assumed speed is adapted to the current speed in a speed model by way of the speed correction term (11).
12. A method according to one of the preceding claims, characterised in that the position of the magnetic flux is determined for determining the flux speed, and specifically by way of the equation $$\rho =\frac{1}{p}\cdot \mathit{Arctg}\left(\frac{\mathit{\psi m\beta }}{\mathit{\psi m\alpha }}\right)$$

    
13. A method according to claim 12, characterised in that the equation (5) is differentiated with regard to time, and the equations (3a) and 4(a) (for computational evaluation of the speed) are substituted into the differentiated equation (5).
14. A method according to claim 11, characterised in that the temporal derivative of the speed, preferably of the first order, is used in the speed model.
15. A method according to one of the preceding claims, characterised in that the speed model is formed by a mechanical equation of state, preferably of the form $$\dot{\omega }=\frac{\mathit{1}}{J}\cdot \left(M-M_L\right),$$

    

    in which

    M is the driving moment

    M_L the load moment

    J the moment of inertia of the rotating load.
16. A method according to claim 15, characterised in that the load moment is equated to zero.
17. A method according to claim 16, characterised in that the drive moment is equated to zero.
18. A method according to one of the preceding claims, characterised in that the load moment is formed by the equation $$M_L=K_{\mathit{1}}\cdot {\omega }^2,$$

    

    in which

    K ₁ is a constant.
19. A method according to one of the preceding claims, characterised in that the drive moment is defined by the equation $$M=K_2\cdot \left({\psi }_{\mathit{m\alpha }}\cdot i_{\beta }-{\psi }_{\mathit{m\beta }}\cdot i_{\alpha }\right),$$

    

    in which

    K₂ is a constant.

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